This application from the University of Pittsburgh proposes an HIV/AIDS Clinical Trials Unit (Pitt CTU) consisting of two Clinical Research Sites (CRS), one at the University of Pittsburgh affiliated with the AIDS Clinical Trials Group (ACTG) and the Microbicide Trials Network (MTN), and one at Georgetown University affliliated with the ACTG. Both Networks have selected the Pitt CTU for affiliation. The Pitt CTU began conducting HIV/AIDS clinical trials in 1986 and has since acquired broad experience in Phase I-IV studies. Under the leadership of J. Mellors (PI), the Pitt CTU became a DAIDS-funded ACTG Unit in 2000. The Georgetown University CRS joined the Pitt CTU in 2001 and remains the only access to DAIDS-sponsored treatment trials in Washington, DC. The Pitt CTU has been a top performing site in the ACTG over the past three years, ranking 5th out of 34 sites in cost efficiency (cost per weighted accrual) and 9th of 34 sites in weighted accrual, with consistently outstanding scores for data management. This strong performance has continued during the current evaluation period (July 2004 - June 2005), with the Pitt CTU ranking 3rd of 34 sites in total accrual, 5th in cost efficiency, 8th in accrual of women, and 4th in data performance. Both the Georgetown and Pitt sites are responsible for this excellent performance. In addition, Pitt CTU investigators have made important contributions to the scientific accomplishments of the ACTG through protocol development, membership on scientific committees, and publication of research findings. The specific aims of the Pitt CTU for this application are: 1) to provide access to DAIDS-sponsored clinical trials for difficult-to-reach populations heavily impacted by the HIV/AIDS epidemic in Washington, DC, and in rural and urban areas of western Pennsylvania and West Virginia, where no other access exists;2) to recruit, screen, and enroll a minumum of 420 participants during the project period in trials addressing the priority areas of translational research and drug development, optimization of clinical management, therapeutic vaccine research and development, and microbicides;3) to advance the scientific agenda of both Networks by developing research protocols, serving on scientific and leadership committees, and directing virology and immunology speciality laboratories;4) to involve and mentor new investigators in HIV/AIDS clinical research;and 5) to partner with the community throughout these endeavors. The investigators and staff of the Pitt CTU are committed to the goal of reducing the impact of the HIV/AIDS epidemic worldwide through translational research to define optimal strategies for treatment and prevention of HIV-1 infection and its complications.